Update Helm chart directory

[bradmccoydev]

update helm chart directory to match https://github.com/ortelius/keptn-ortelius-service/tree/master/helm/keptn-ortelius-service

now the charts are in the "chart" folder for the testkube-executor-keptn

We need to change this directory structure to match the keptn-ortelius-service so rename it to helm and put another subfolder inside it called testkube-executor-keptn.

Also have a look through the files to understand them and see if there is anything else you think we need to change.

@Vrukshali-26 will take this one